seb

I think given the last sentence of your post, I'll leave you to it rather than responding and discussing "correctness".

A trend? Models jumping back and forth. If the next 4 ECM runs and the next 8 GFS runs show everything staying norths or moving west, then we can talk about a trend.

This 100%. I'm just baffled how some people can be watching each run frame by frame to then spot random features being introduced or moved around by a few hundred miles. I mean for heaven's sake, we suddenly have a channel low showing up of the GFS Op out of the blue. If that isn't telling that all the models are struggling with how to handle the huge pool of cold air and the blocking off of the Atlantic then I don't know what would. I'm going to say it again. BIG picture. That has not changed in days. It will be colder from next week and much colder from the latter part of next week. All the potential we can possibly ask for is there and that is exceptional for this time of year.

Beautiful. GFS kills the low roundabout 236 hours and pushes its remains to the SE without ever coming close to impacting us. Makes much more sense than what the ECM produced earlier. Exactly what you'd expect with that huge area of high pressure blocking the low and also in line with jet (which the ECM's solution was not).

While there's a valid point in what you're saying (i.e. setup from day 6 leads to what is shown for day 9+) , the ECM wants to create a low which is far, far too intense to be plausible. That's not surprising given what it is trying to do but it's also not going to verify like that (just look at the mean vs the op). It follows that with a chunk of the intensity of the low being removed the cold isn't going to be pushed back as far as shown in the latter part of the op and we end up far closer to what is shown on other models.

GFS 00z, ECM 00z and ECM 12z at Friday 9 Dec 12pm. No point going any further right now. All three are excellent and all three are similar. Anything beyond that is FI at the best of times and more so in this setup.

And once again, a perfectly normal model wobble-about of 200 miles at 9 days from now is causing doom and panic. Please look at the big picture. Please remember how much models struggle in this kind of setup. The overall setup has not changed, it remains brilliant and extraordinary for early December.

ECM and GFS

I think the differences are far greater than similarities?

I mean I won’t ever take snow charts seriously even within a 24 hour time frame but I’ll bank 4cm and lows of -6 for my neck of the woods a week from today

And at 144 it still looks great

Lol. I think it’s a beauty so far.

ECM wobble corrected by the looks of it.

Those are some really good charts so far this afternoon. Let's see what the ECM will do.

NYE 1978 - I was only a few months old but my parents had a party in our new house. People arrived in pouring rain. By midnight there were nearly 10cm of snow. By 3am it was up to 20cm and when everybody woke up around 10am there was well over 30cm, blue skies and a hard frost. My parents still talk about it. Never seen anything like it before and never since. They lived in central Germany at the time but from what I know things were similar everywhere?

It’s good enough for me lol. And of I had to bet I’d say it’ll look just fine again in the next run or the one after that

Don't think there needs to be any hero lol. Every single model is going to wobble a bit. This kind of setup is always confusing to the models and every time they try do weird things in one run which then completely vanish in the next.

But it isn’t a given for many. I’m not going to argue and I know what you meant and mean but many don’t. I think it’s great that we have a lot of people who are interested but not as knowledgeable as others and I just think that it’s important to be clear when analysing individual runs.

So really what you wanted to say was: If the ECM Op verified as per this morning’s run then we’d end up with cold rain for most. That’s valid and I assume that’s what you meant. But what you actually said, together with the general OTT reaction by some, implies to those less knowledgeable that instead of cold and potentially snow we are now expecting miserable wet and cold weather which simply is not true.

Come on. You posted a chart from the ECM Op for 10 December and said “cold rain for most”. There’s loads of people here who don’t have your knowledge and will take that as what will happen.

One word… CALM. Models will wobble as always in this kind of setup. There’s no point worrying about “too far west” on charts showing a potential scenario at 9+ days and there’s definitely no reason to predict “cold rain” for all on 10 December. The overall setup hasn’t changed.

Calm needed. Ignore individual runs and look at the big picture. A change in pattern is about to occur and the train of one front from the Atlantic after another is about to end. All possibilities that come with the pattern which is about to be in place are in play. No one promised snow, no one promised there would be a BFTE, no one has mentioned extreme cold. However all of those are possibilities as is a return to a dominating Atlantic or calm, grey boring cool/cold weather. One fact remains - it’s been years since we had a setup this early in winter that allows for all those possibilities.

Looks like some exciting times ahead As always, it is good to remember not take individual runs in isolation, not to take the Ops as gospel and to look at the overall patterns. Anything 8+ days is FI but if Models overall are close with their solutions then that is good guidance.

Rain!! We have proper rain with puddles

It’s much more accurate. It wouldn’t have been possible to more or less nail down a heatwave 14 days in advance. But models are based on previous data, behaviour and outcome. If something changes in way that hasn’t happened inside the period which models have access to then they’ll struggle. Of course all the investments are not only aimed at mid-range forecasting and its accuracy. Huge sums are invested in more and more accurate short term modelling which is extremely important for flooding, tornadoes, storms and so on.